As known, the common computer input device includes for example a mouse device, a keyboard, a trackball, a touchpad, and the like. Among these input devices, the mouse device is the most prevailing because it complies with the usual practices of most users. When a mouse device is held by a user's palm, the user may move the mouse device to control movement of the cursor shown on the computer screen.
FIG. 1 is a schematic diagram illustrating the connection between a conventional mouse device and a computer system. The computer system 2 comprises a computer host 21 and a computer monitor 22. The computer host 21 is in communication with a wheel mouse device 1 and the computer monitor 22. A cursor 221 is displayed on the computer monitor 22. The wheel mouse device 1 is used for controlling the cursor 221 to have the computer host 21 execute a corresponding instruction. The wheel mouse device 1 comprises a mouse body 10, a left button 11 and a right button 12. The mouse body 10 is used for supporting a user's palm. When the mouse body 10 is moved by the user to result in a displacement amount, the computer host 21 correspondingly moves the cursor 221 shown on the computer monitor 22 according to the displacement amount. By clicking the left button 11 or the right button 12, a control signal is issued to the computer host 21. In response to the control signal, the computer host 21 executes a corresponding instruction. The basic functions of the wheel mouse device have been described above.
Generally, for different users, the size of the palms and the length of the fingers are different. Since the mouse body of the common mouse device has a fixed size, the mouse device may only comply with the palms and fingers of specified users. In other words, the size of the mouse body of such a mouse device fails to comply with the palms and fingers of some other users. If the unsuitable mouse device is used for a long time period, the procedure of operating the mouse device usually incurs unacceptable fatigue of the user's hand.
Therefore, there is a need of providing a mouse device for complying with various-sized palms.